1.题目描述：点击打开链接
2.解题思路：本题通过观察发现，如果两个数a,b的最大公约数是G，那么G≤a且G≤b。因此直接令a=G即可。如何判断是否有解呢，，只需要看是否满足gcd(G,L)==G就行了。如果满足，b=L。
3.代码：
#define _CRT_SECURE_NO_WARNINGS #include<iostream>#include<algorithm>#include<string>#include<sstream>#include<set>#include<vector>#include<stack>#include<map>#include<queue>#include<deque>#include<cstdlib>#include<cstdio>#include<cstring>#include<cmath>#include<ctime>#include<functional>using namespace std;typedef long long ll;typedef unsigned long long ull;typedef pair<int, int> P;typedef pair<long long, long long> PL;#define me(s) memset(s,0,sizeof(s))#define For(i,n) for(int i=0;i<(n);i++)int gcd(int a,int b){return b == 0 ? a : gcd(b, a%b);}int main(){//freopen("t.txt", "r", stdin);int g, l;int T;scanf("%d", &T);while (T–){cin >> g >> l;int gg = gcd(g, l);if (gg == g)printf("%d %d\n", g, l);else puts("-1");}return 0;}
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